The placenta grows and adapts during pregnancy to meet the demands of the developing fetus and to respond to changing conditions of the maternal environment. One of the most common causes of pregnancy complications is for the blood vessels within the placenta to develop in an abnormal arrangement, reducing the oxygen and nutrients transferred from the mother to the fetus. Diagnostic ultrasound is the current gold standard for detecting placental problems during pregnancy. Abnormally pulsatile flow in the umbilical cord arteries is an indicator that the downstream vessels are improperly formed. Unfortunately, this approach for detecting placental abnormalities is not always accurate, particularly when abnormalities arise late in gestation. We propose to develop a new method for obtaining more accurate diagnostic information from ultrasound data based on the timing of pressure and blood flow changes within the umbilical cord blood vessels. We will validate this technology using experimental mice that mimic common and severe pregnancy complications. We will also translate the non-invasive method to evaluate human pregnancies. For this, we will conduct a study of pregnant women who are referred for ultrasound either as part of routine screening or because they have been identified as at risk of pregnancy complications. With these data, we will develop criteria for detecting abnormal placental blood flow and compare these with established ultrasound criteria as well as with pathology assessment at birth. The widespread use and availability of ultrasound provides a clear path for clinical translation of the developed technology. Thus, the proposed studies could significantly enhance women's and fetal health through better management of healthy and at-risk pregnancies.